Control device



June 1, 1937. w. 1.. S'TUYVERSON CONTROL DEVICE Filed July 27, 1932 2Sheets-Sheet 1 Patented June 1, 1937 it UNITED STATES PATENT OFFICECONTROL DEVICE William L. Stuyverson, Elkhart, .Ind. Application July'27, 1932, Serial No. 625,024 14 Claims. (Cl. 236-46) This inventionrelates to stoker operation and tionof shaft it. The number of fingersup n the like, and among other objects aims to pmthe shaft dependssomewhat upon t Spe d Of vide an improved thermostatic control device aon f t e S a t In t present instance which is efiicient in operation andsimple and inthe shaft is driven slowly and makes one revoluexpensive inconstruction, for controlling the on in about one' o s time A Springclock operation of domestic stokers. mechanism or electric clock forthat reason may 'The inventionmay be readily understood byadvantageously be used to rotate shaft I6, a1- reference to anillustrative construction embodyt ough it is obvious that any otherdriving meching the invention and shown in the accompanyanism would beequally satisfactory. The shaft I0 ingdrawings, driving mechanismv isindicated at I8 and is In said-drawings: cated at one end of theenclosure [9 surrounding Fig. l is an elevation, somewhat diagrammaticthe Control pp in character, showing therelation of the control rI'heControl mechanism is s c d a d a deviceto one-form of d ti t k ranged sothat one of the fingers, that here Fig. 2 is a transverse verticalsection of the marked a t s thestoker m an mn control device taken onthe plane 22 of Fi 4 each revolution regardless of temperature deshowingthe controlling element; mand, and thus functions as the means'for main-Fig. 3 is a plan View of the device taken just taining a minimum fire inthe furnace. For below the cover of its enclosing housing; ordinarydomestic use,-the finger 2E9 actuates the Fig, a is a longitudinalsection taken on the Stoker for about five minutes once each hour, plane4-4of Fig. 2; and during which small periodic charges of fuel ag- Figs.5 and 6 are detail views illustrating the gregatihg a u five 1301111613are fed into the operation of the control mechanism. fire-box. Themechanism is also constructed and The illustrative control device ishere shown a ra ged so t t he o e fingere Operate applied to a rotarydomestic stoker of the type ill c ve y depe p the temperature lustratedin my copending application, Serial mend. No. 584,503, althoughcit isobvious that use of The fingers I! and 29 are arranged to close an thecontrol device is not limited to stokers of electric contact when theyar ive at a given'peint this type. The aforesaid rotary stoker l0 feedsin order to operate the stoker, said electric concoal periodically insmall charges through the tact being here shown in the form of arockable feeding tube H into the furnace I2 and allows mercury switch 2|whose terminals 22 are conit 'to drop upon'the The. The amount of eachnected by a quantity of mercury 23 inside the charge is made smallenough so that any smoke tube when the latter istilted to cause themercury which may be generated by contact .of the fuel to flow towardthe contacts. Wires 24 are conand willnot'pass up "the stock. Deliveryoflperent to motor M. The switch is shown pivoted riodic charges of'fuel is e'irecte'd by,-placing'one or at 25 to the structure of thedriving mechanism more baffles'inside'the rotary coalhopperi3which, l8and is provided with an operating lever 26 upon rotation of the hopper,cause a quantity of projecting, in this case downwardly, into the 4 fuelto be dropped into'th'e open upper side of path of the operatingfingers. The switch is tube i I through which it is conveyed by 'aiscrewrocked'to close the circuit when the finger 20 for conveyor or thelike'into the fire-box. The hopexample engages lever 26 and as soon asthe peris :rotatedbya motor M geared with the gear bottom of the mercurytube is tilted 'just beyond ring IS on the hopper. The intensity of thelevel position so that the mercury flows toward fire maybe varied-byvarying theifrequency with the terminals 22 where it remains so long asthe which ,the hopperis operated. tube is held tilted by finger Zil. Tocontrol The illustrative control device is adapted to duration of theperiod when the'switch is closed, actuate the stoker at relativelyinfrequent interthe end of lever 26 is provided with a cam surface Valsto maintain aminimum fire and also to El laterally projecting in o the pof finger 5-0 actuate it periodically at shorter intervals de- 29. Theunder face of the cam is here shown pending upon the temperature demand.The acwith a longitudinal convex curvature correspondtuating element .ishere represented by a rotating somewhat to that of the arc traversed bying shaft [6 havinga plurality of control fingers the ends of fingersand arranged (when the I! adapted in the event of temperature demandswitch is in closed position) so that its outer end each to actuate thestoker once for each revolu- 28 is somewhat closer the center of shaft I6 with 'the'hot'fire will be substantially consumed nected through asource 25 of the electric cur- U than its front end 29. This insuresthat the switch will be held in closed position from the time it issufilciently tilted by engagement of the finger with the projecting edge29 until the finger traverses the entire length of the cam surface 21.In the present instance, this period is in the neighborhood of fiveminutes where the shaft rotates about one revolution per hour. This period may be varied by varying the length of the cam surface 21 and forthat purpose one portion 30 of the cam surface may be madelongitudinally slidable relative to the other portion 3|. For purposesof adjustment the flange 32 of the movable section of the cam is slottedand held in adjusted position relative to the other portion 3| by meansof a bolt 33 or the like.

When a. finger clears the outer end of cam 23 the switch is released andtilts in the opposite direction to open the circuit. A pin 35 limits thebackward tilting of the switch.

To secure the selective action of the control fingers l1 in response totemperature demands, the mechanism is arranged so that they may be madeto engage or clear the lever 26 depending upon whether or not additionalfuel is required. As here shown (see Fig. 4) fingers 11 are bentoutwardly at their extremities so that normally they clear the extremityof lever and the cam 21. They are actuated to engage cam 1 in responseto temperature demands by a thermostatically controlled guide bar 36whose end M has a tapered or cam like outline adapted to engaged by theextremities of fingers ii and to be cammed or guided inwardly (see Fig.i) into alinement with cam 21. The guide bar 35 is in this instancecontrolled by a bi-metallic thermostatic element 38 supported on a rodand to one end of which the guide bar is connected. The other extremity4B of the thermostatic element is connected to a pivoted adjusting leverM which may be rocked back and forth through a limited arc to vary thetemperature at which the guide bar acts. The lever has an operatingfinger passing through a slot in the housing adjacent which is atemperature scale by which the necessary adjustment of the thermostatmay be regulated by moving the finger to the right or left.

When the room temperature (in which the thermostat is located) exceedsthe desired maximum, the thermostat raises bar 38 upwardly beyond theend of fingers l1 which therefore do not actuate the stoker. When thetemperature reaches the predetermined minimum, the bar 36 is lowereduntil it comes into the path of fingers l1 which are then guided overinto alignment with cam 21. If a finger l1 has once been placed inoperative connection with cam 21 it is held against springing out bychanneling the under face of the cam to provide a downwardly extendingflange 42 which constrains fingers 11 to travel along cam 21 until theyclear its end 28.

A stop in the form of an inwardly projecting bar 43 is provided toprevent excessive lowering of the guide bar 36 to a point beyondoperative engagement with fingers 11, in the event of a sudden chillingof the thermostat by an open door or window. Thus for all temperaturesbe low the minimum at which the device operates, the guide bar 36 isalways in operative relation to the fingers 11.

The normal minimum duration of the switch closure may be further reducedif it seems desirable by tilting the entire control device in aclockwise direction (see Fig. 2). This has the effect of requiringadditional travel of the fingers H or Ell (after they are in engagementwith cam 21) before the switch tube 2i is tilted beyond level positionto cause the mercury to fiow toward the contact end of the tube. Tiltingof the device may be effected in any appropriate manner such as by screw44 adapted when driven down to elevate one edge and thus rotate thecontrol device in a clockwise direction.

If shaft Iii be driven by clock spring motor, switch 3i mayadvantageously be counter-weighted to avoid the possibility that themotor may run down when the switch is closed and thus indefinitelycontinue the operation of the stoker. The counter-weight 45 increasesthe resistance to rocking of the switch to closed position so thatunless the spring motor has enough residual energy to continue inoperation long enough to carry a finger beyond the cam (and therebyallow the switch to open) it will not be powerful enough to tilt theswitch to close it. In the latter case the will be stopped when itencounters the forr-v'ard edge 29 of the cam, since the greatest forcemust be initially exerted to start the rocldng movement of the switchunder the resistance of both the mercury and the counter-weight.

Obviously the invention is not limited to the details of theillustrative construction since these may be variously modified.Moreover it is not indispensable that all features of the invention heused conjointly since various features may be used to advantage indifferent combinations and sub-combinations .i-laving described myinvention, I claim:

. In apparatus of the character described the 1 comprising a stokeradapted to feed u" emerges of fuel, a motor for operating a motorswitch, a rotating control ng switch actuating members projecting th canfor periodically closing said switch upon rotation oi said device, andmeans for rendering a member inoperative to close the 2. In apparatus ofthe character described the combination comprising a Stoker adapted tofeed periodic charges of fuel, a motor for operating said stoker, amotor switch, a rotating control device having switch actuating membersprojecting therefrom and adapted periodically to actuate said switch,and thermostatically controlled means for moving said members intooperative relation to said switch.

3. Stoker control apparatus of the character described comprising incombination an electric switch, a continuously rotating shaft having aplurality of switch operating fingers projecting therefrom and arrangedso as normally to clear said switch upon rotation of said shaft, and athermostatically actuated member adapted at low temperature to move saidfingers into operative engagement with said switch.

4. Stoker control apparatus of the character described comprising incombination an electric switch, a continuously rotating shaft having aplurality of switch operating fingers projecting therefrom and adaptedperiodically to engage and close said switch for limiting periods oftime, and a temperature controlled device for rendering a fingerinoperative when minimum temperatures are exceeded.

5. Stoker control apparatus of the character described comprising incombination an electric switch, a continuously rotating shaft having aplurality of switch operating fingers projecting therefrom, certain ofsaid fingers being arranged so as normally to clear said switch, and atemperature controlled device for moving a finger into operativerelation to said switch at low temperature.

6. Stoker control apparatus of the character described comprising incombination an electric switch having a projecting cam, and rotatingswitch fingers adapted periodically to engage said cam toclose thecircuit during the period of contact with said cam, one or more of saidfingers being displaceable to effect cam engagement.

'7. Stoker control apparatus of the character described comprising incombination an electric switch having a projecting cam adjustable inlength, and rotating switch fingers adapted periodically to engage saidcam to close the circuit during the period of contact with said cam,said cam being adjustable to vary the duration of contact therewith.

8. Stoker control apparatus of the character described comprising incombination an electric switch, a continuously rotating shaft having aplurality of switch operating fingers projecting therefrom and arrangedso as normally to clear said switch upon rotation of said shaft, athermostatically actuated member adapted at low temperature to move saidfingers into operative engagement with said switch, and another fingeron said shaft arranged to actuate said switch independently of saidthermostatically actuated member.

9. Stoker control apparatus of the character described comprising incombination an electric switch having a rocking cam adapted to be rockedto close the electric circuit, a plurality of moving fingers adaptedperiodically to engage said cam to close the circuit and means forvarying the frequency of engagement of said fingers with said cam, bydisplacing one or more of said fingers.

10. Stoker control apparatus of the character described comprising incombination an electric switch having a rocking operating cam with achanneled face, a plurality of moving fingers for engaging said cam toclose the switch, said fingers being arranged so as normally to clearsaid cam, and means for engaging said fingers to cause the same toengage the channel of said cam, said channel serving to preventpremature disengagement from said cam.

11. Stoker control apparatus of the character described comprising incombination an electric switch having a rocking operating cam with achanneled face, a shaft having a plurality of spring fingers projectingtherefrom and normally arranged to clear said cam, and athermostatically controlled guide for engaging said finger to move thesame into register with the channel of said cam.

12. Stoker control apparatus of the character described comprising incombination an electric switch having a rocking cam adapted to be rockedto close the electric circuit, a plurality of moving fingers adaptedperiodically to engage said cam to close the circuit, and means forvarying the frequency of engagement of said fingers with said cam, saidmeans including thermostatically actuated means for displacing one ormore of said fingers.

13. Stoker control apparatus of the character described comprising incombination an electric switch having a movable cam adapted to be movedto close the electric circuit, a plurality of moving fingers adaptedperiodically to engage said cam to close the circuit, and means forvarying the frequency of engagement of said fingers with said cam, saidmeans including temperature actuated mechanical means for displacing oneor more of said fingers.

14. Control apparatus of the character described, comprising an electricswitch, a continuously rotating shaft having a plurality of equallyspaced switch actuating members, one of said members set to actuate saidswitch each revolution of said shaft, and temperature controlled meansadapted to selectively operate the remaining member to actuate saidswitch as temperature setting demands.

WILLIAM L. STUYVERSON.

